EUV light source and apparatus for EUV lithography

Abstract

A metal reuse system for an extreme ultra violet (EUV) radiation source apparatus includes a first metal collector for collecting metal from vanes of the EUV radiation source apparatus, a first metal storage coupled to the first metal collector via a first conduit, a metal droplet generator coupled to the first metal storage via a second conduit, and a first metal filtration device disposed on either one of the first conduit and the second conduit.

What is claimed is: 
     
       1. A method of operating an extreme ultra violet (EUV) radiation source apparatus, comprising:
 generating metal droplets by a droplet generator; 
 irradiating the metal droplets with an excitation laser; 
 collecting metal debris from an inside a chamber of the EUV radiation source apparatus; 
 storing in a storage the collected metal debris; 
 supplying the metal debris from the storage to the droplet generator; and 
 filtering by a filter the metal debris before transferring the metal debris to the droplet generator. 
 
     
     
       2. The method of  claim 1 , wherein the metal debris is filtered before the metal debris is stored. 
     
     
       3. The method of  claim 1 , wherein the metal debris is filtered after the metal debris exits from the storage. 
     
     
       4. The method of  claim 1 , further comprising heating the storage. 
     
     
       5. The method of  claim 1 , further comprising pressurizing the storage. 
     
     
       6. The method of  claim 1 , wherein the filter includes a porous membrane to filter particles having a size greater than 1.0 μm. 
     
     
       7. The method of  claim 1 , wherein the filter includes a ceramic filter. 
     
     
       8. A method of operating an extreme ultra violet (EUV) radiation source apparatus, wherein the EUV radiation source apparatus comprises:
 a droplet generator for generating metal droplets; 
 a first metal collector for collecting metal debris from an inside a chamber of the EUV radiation source apparatus; 
 a first metal storage coupled to the first metal collector via a first conduit; 
 a second conduit coupled to the first metal storage; 
 a first metal filtration device disposed in either one of the first conduit or the second conduit; 
 a first pressurizing device coupled to the first metal storage via a third conduit; 
 a first valve disposed on the first conduit; 
 a second valve disposed on the second conduit; 
 a third valve disposed on the third conduit; and 
 a controller that controls the first pressurizing device, the first valve, the second valve, and the third valve, 
 the method comprising: 
 collecting the metal debris from the inside of the chamber of the EUV radiation source apparatus; 
 storing in the first metal storage the collected metal debris; 
 closing the second and third valves and opening the first valve when an amount of metal in the droplet generator is more than a threshold amount, and 
 supplying the metal debris stored in the first metal storage by operating the first pressurizing device and opening the second valve and the third valve and closing the first valve, when the amount of the metal in the droplet generator becomes equal to or less than the threshold amount. 
 
     
     
       9. The method of  claim 8 , further comprising heating the first to third conduits at a temperature higher than a melting point of the metal. 
     
     
       10. The method of  claim 8 , further comprising filtering by a filter the metal debris before transferring the metal debris to the droplet generator. 
     
     
       11. The method of  claim 10 , wherein the filter is disposed on the first conduit. 
     
     
       12. The method of  claim 10 , wherein the filter is disposed on the second conduit. 
     
     
       13. The method of  claim 10 , wherein the filter is disposed on each of the first conduit and the second conduit. 
     
     
       14. The method of  claim 10 , wherein the filter includes a porous membrane to filter particles having a size greater than 1.0 μm. 
     
     
       15. The method of  claim 10 , wherein the filter includes a ceramic filter. 
     
     
       16. A method of operating an extreme ultra violet (EUV) radiation source apparatus, wherein the EUV radiation source apparatus comprises:
 a metal collector for collecting metal from an inside a chamber of the EUV radiation source apparatus; 
 a metal storage coupled to the metal collector via a first conduit; 
 a second conduit coupled to the metal storage; and 
 a metal filtration device disposed either one of the first conduit or the second conduit, 
 the method comprising reusing the metal collected by the metal collector in a droplet generator after the metal is filtered by the metal filtration device. 
 
     
     
       17. The method of  claim 16 , wherein the metal collector is a heated tin vane bucket. 
     
     
       18. The method of  claim 16 , wherein the metal collector is a droplet catcher of the EUV radiation source. 
     
     
       19. The method of  claim 16 , wherein the metal filtration device is disposed on each of the first conduit and the second conduit. 
     
     
       20. The method of  claim 16 , wherein the metal filtration device includes a porous membrane to filter particles having a size greater than 1.0 μm.